Managing cases

The bone in contact with the root surface (called bundle bone) contains the collagen bundles from the periodontal ligament. The speaker said we can think of the bundle bone as a mineralised extension of the periodontal ligament. In the same way that the dental cementum is the mineralised ‘end’ of the periodontal ligament and connects the tooth to the periodontal ligament, the bundle bone is another mineralised end of the periodontal ligament which connects the ligament to the skeleton.

“We can think of the bundle bone as a mineralised extension of the periodontal ligament”

The speaker then posed the question: how much of the buccal bone wall is bundle bone? In 2011, the thickness of the buccal bone wall in the aesthetic zone was measured in 250 individuals. It was found that the average buccal bone wall was 0.6mm. The buccal wall was greater than 1mm in only around 15% of individuals included (Januário et al. 2011).

Significant anatomical differences can be found in the dimensions of the alveolar process and in the angulations of the roots relative to bone inclination.

The alveolar socket can be thought of as an ideal four-wall ‘bone defect’ which has very good blood clot stability, blood supply and cell source. The speaker described the histological healing process of the socket, which had been illustrated in a previous publication (Araújo & Lindhe. 2005). In this publication, the dimensional changes which the alveolar process and buccal crest underwent were highlighted.

“The alveolar socket can be thought of as an ideal four-wall ‘bone defect’”

This marked reduction of alveolar dimension has been clinically measured in CBCT studies comparing the alveolar process surrounding teeth with edentulous alveolar ridges in the anterior maxilla (Misawa et al. 2016; Chappuis et al. 2013). Thin-wall phenotypes were found to suffer a mean bone loss of 7.5mm while thick-wall types decreased by only 1.1mm.

The speaker concluded his presentation by saying that clinicians should acknowledge the importance of buccal bone wall thickness. They should recognise that tooth extraction will be followed by ridge reduction, and further clinical steps should be considered to compensate for this loss.

“Clinicians should acknowledge the importance of buccal bone wall thickness”